1. Field
Example embodiments relate to an apparatus for manufacturing a semiconductor device, and a method for manufacturing a semiconductor device using the apparatus.
2. Description of Related Art
Semiconductor device manufacturing may include a photolithography process for integrating a plurality of components into a semiconductor device. A photolithography process may employ a photoresist to form a required pattern. For example, the dimensions of a semiconductor device pattern may rely on the resolution of a photolithography process. As semiconductor devices require higher degrees of integration, photolithography processes capable of realizing superior resolution may be needed.
The resolution in a photolithography process may be determined by Rayleigh's equation: R=kλ/NA. Here, k may be a resolution factor, λ may be a wavelength of the exposing radiation, and NA (numerical aperture) may be an effective aperture of a lens. Accordingly, the smaller the resolution factor and wavelength of the exposing radiation may be, and the greater the numerical aperture may be, the finer patterns may be formed.
To form miniature patterns, a short wavelength of the exposing radiation may be used. For example, wavelengths of the exposing radiation of 248 nm krypton fluoride (KrF) or 193 nm argon fluoride (ArF) may be used.
Also, in order to form miniature patterns, the numerical aperture of a lens may be increased. The effective aperture of a lens, for example, the NA, may correspond to n·sin θ. Here, n may be the refractive index of the medium between the lens and photoresist, and θ may be the acceptance angle. Accordingly, the higher the refractive index of the medium, the higher the resolution may be in a photolithography process. In general, an exposure in a photolithography process may be performed under atmospheric conditions. For example, air, with a refractive index of 1.0 may be used as a medium for exposing radiation between a light source and a photoresist. However, as design rules may be reduced, the use of air as a medium in photolithography processes to form more miniaturized patterns may have limitations. Thus, in order to overcome resolution limitations, immersion lithography has been introduced.
In immersion lithography processes, water, organic solvents and other liquids having a refractive index of 1.0 or higher may be used as a medium between a light source and a photoresist. Accordingly, the NA of a lens in an immersion lithography process may be increased versus that in a typical photolithography process. For example, resolution may be raised through reducing a wavelength of incident light from an original value to a smaller value. However, immersion lithography processes may involve limitations brought about by a liquid residing for a prolonged period on a substrate.